This invention pertains to a gyro orienting system in which a quick start device to bring the gyro up to speed and known orientation is essential because resort to reliable external magnetic signals or any other reliable external signals is virtually impossible. The field of invention exists because in modern warfare many self-propelled vehicles such as tanks, weapons carriers, boats, ships, planes, rocket launchers, jeeps, artillery and the like are operated over unfamiliar terrain and under extremely difficult navigational conditions caused by weather and hostile or friendly military action which may not only destroy known landmarks but through the use of atomic weapons reorient local magnetic fields.
In addition, because of the confusion involved in battle and the possibility that an enemy could attempt to disorient crews of such self-propelled devices, no resort can be had to external navigational aids such as radio signals and the like. Therefore, a navigational system for such a self-propelled device must have a fixed reference contained within itself. Because such vehicles disturb the accuracy of magnetic readings in their immediate vicinity a magnetic compass is unsuitable to use as the fixed reference. In addition, local magnetic variations and the possibility of atomic warfare creating magnetic disturbance make magnetic compass readings both within and without the vehicles excessively unreliable.
The range of self-propelled military vehicles and the like is generally quite limited because the space available for carrying fuel safely is very limited and because a large portion of the vehicle's payload is devoted to its principal mission of being a weapons carrier. Accordingly, when the vehicle is not actually in operation its electrical system must be shut down to conserve fuel. When such a vehicle is de-energized the gyro orienting system is also turned off. Naturally, when the vehicle has to move great danger can attend any delay in its motion because of the risk of hostile enemy infantry, air and artillery attacks.
There are gyro systems which initially orient themselves by use of a ballistic pendulum. These devices are quite accurate but, when turned off, tend to disorient themselves while running out and require a minimum of 15 to 20 minutes to reorient themselves.